Potential employer is requesting a visit and is on the other side of the country. Job offer not made yet, whats the professional response?

“I have not budgeted or planned on a trip at this point in time. If a visit is a prerequisite to recieving a job offer, I will need my travel expences covered. If the visit is not necessary in order to recieve the offer, I’ll kindly ask to sort that out first, prior to moving forward with any travel plans.”